Estimates of the air-fuel ratio at the time of ignition in a pre-chamber using a narrow throat geometry

Ponnya Hlaing, Mickael Silva, Manuel Echeverri Marquez, Emre Cenker, Moez Ben Houidi, Hong G. Im, James WG Turner, Bengt Johansson

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


The benefits of pre-chamber combustion (PCC), such as improved engine efficiency and reduced NOx emissions, are primarily observed when operating at lean conditions with an active pre-chamber, where auxiliary fuel is supplied directly to the pre-chamber. Estimating the pre-chamber excess air ratio (λ) is important in the active pre-chamber concept to gain insights into the pre-chamber combustion phenomenon. Experimental investigations were performed using a narrow-throat pre-chamber at global-λ 1.6, 1.8, and 2.0. The fraction of fuel energy injected in the pre-chamber over the total fuel energy was fixed at 3%, 7%, and 13% for each global-λ. The mixture formation process inside the pre-chamber is first simulated using the 1-D simulation software GT-Power to analyze the pre-chamber λ at the ignition timing. However, the 1-D results were unable to reproduce the experimental observations on the pre-chamber pressure buildup accurately. Upon simulating the same conditions using the 3-D CFD software CONVERGE, the pre-chamber λ estimated from the CFD model is well-correlated to the experimental data. The CFD results indicate that the amount of fuel trapped in the pre-chamber at the inlet valve closing timing is over-predicted by the 1-D simulations. A correlation between the injected and the trapped fuel in the pre-chamber is proposed by theoretical scavenging models and applied to the 1-D simulation results to improve pre-chamber λ prediction accuracy.
Original languageEnglish (US)
Pages (from-to)146808742110591
JournalInternational Journal of Engine Research
StatePublished - Dec 15 2021

Bibliographical note

KAUST Repository Item: Exported on 2021-12-21
Acknowledged KAUST grant number(s): FUELCOM Agreement Number 6600024505/01
Acknowledgements: The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: The paper is based upon the work supported by Saudi Aramco Research and Development Center FUELCOM3 program under Master Research Agreement Number 6600024505/01. FUELCOM (Fuel Combustion for Advanced Engines) is a collaborative research undertaking between Saudi Aramco and KAUST intended to address the fundamental aspects of hydrocarbon fuel combustion in engines, and develop fuel/engine design tools suitable for advanced combustion modes

ASJC Scopus subject areas

  • Mechanical Engineering
  • Ocean Engineering
  • Automotive Engineering
  • Aerospace Engineering


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